Silage season has really burst into life in the last fortnight, with many farmers already having completed first cut.

As one long day runs into another, for contractors and farmers alike the name of the game will be machinery maintenance in order to give the best chance of avoiding expensive downtime and needless repairs.

This week I run through some of the key maintenance points you should look out for an older silage mower conditioner. From the pictures you can see we go from the drawbar right through to the conditioner, and explain what to look out for.

It's a good idea to have a few of the most commonly used spare parts in the van so that they are available when needed - knives, belts and replacement oil. It is helpful that most good dealerships are offering extended out of hours service during the busy summer months, with extra staff laid on for on call management of machinery breakdowns.

KEEP IT OILED

Use 80/90 gear oil in both the swivel hitch gearbox and the main gearbox at the slip clutch. This oil should be changed once a year and should be checked regularly. In this picture we are looking at the top and bottom gearboxes of the swivel hitch. This mower (an older John Deere model 1316) takes 0.8 litres of oil in the bottom and 2.4 litres in the top compartment.

WEAR AND TEAR ON THE JOINTS

Watch out for wear in the knuckles of universal joints. As always, make sure your PTO covers and holding chains are in place. Heavy knocks to the mower can crack the drawbar so check its structure regularly.

If you find the mower gets clogged up in only moderately heavy grass one of two things can be wrong. Either the triple v-belt (above) that drives the conditioner needs to be replaced or it needs to be tensioned.

MISSING SKIDS ON DRUMS

In this picture you can clearly see the missing skid on the third drum from the right. A missing skid means that drum will be cutting closer to the ground than its neighbours. It also increases the likelihood of bending/breaking the knives on that particular drum. Skids can either be knocked off with stones/earth or can simply come off as a result of wear and tear. A skid should last at least one season or 1000 acres, whichever comes first.

DRUM DEFLECTOR STRIPS

The two large drums at either end of the cutterbar are often called ‘top hats’ due to their shape. Top hats play an important role in pushing the cut grass into the path of the conditioner. If you look closely you will see deflector strips on them. These are the parts of the drum that actually push the grass into the conditioner. Keeping these deflectors in good shape means the whole sward will be pushed into the path of the oncoming conditioner.

CONDITIONER SPIKES

The conditioner is key to silage quality and so you should check it regularly. Worn bushels will make conditioner spikes spin out of balance and in some cases come off, causing heavy vibration. If you feel this happening, check the conditioner for loose or missing spikes.

SKID KNIVES

Knives need to be replaced when damaged or after 500 acres, whichever comes first. Replacing knives without replacing the skid underneath is only a short-term solution; if the skid is worn and you ignore it, you are throwing good money after bad on replacement knives.

10 steps to better mower conditioner performance

Use 80/90 gear oil in both the swivel hitch gearbox and the main gearbox at the slip clutch. This oil should be changed once a year and should be checked regularly during the silage season

Following the drive shaft back to the slip clutch, watch out for wear in the knuckles of universal joints. Make sure your PTO covers and holding chains are in place.

Set up the flotation springs correctly and grease the top links that are used to set cutting height.

Most mower-conditioners use a triple V belt to drive the conditioner. If you find your mower gets blocked in heavy grass then the V-belt is slipping — either the belt needs to be tensioned or replaced.

The cutterbar oil bed takes around 2 litres of 80/90 oil. This should be changed every season. Before draining oil, it’s a good idea to run the mower for a minute. This heats up the old oil and allows it to flow out of the drain hole faster. The mower should be jacked up on its left side to give a fall for the oil.

Underneath the cutterbar, check the skids regularly. The fastest way to damage

your knives is to continue cutting with skids broken or missing. Skids should normally last for a good 1000-acre season.

Check deflectors on top hats (large drums on either side of cutter bar) for wear. Replace as needed.

Knives should be replaced when damaged or after 500 acres, whichever comes first.

Keep a close eye on the conditioner. Worn bushels will make conditioner spikes spin out of balance or even detach, causing heavy vibration. If you feel this happening, check conditioner for loose spikes.

Check the cutterbar drums for loose bearings. If badly worn these bearings can drop down into the cutterbar gearbox and do untold damage to the gear teeth. Again, heavy vibration is a telltale sign of a worn bearing.